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Mazda 3 AC smell

Hi Everyone,

I have a 2011 Mazda 3i Touring sedan and whenever I turn on the air conditioning a smell as if somebody has been sick comes out of the vents for the first minute. Is there any explanation for this or am I just stuck with a smelly AC.


Did you buy this new or used?
Does it have a cabin air filter?

I bought the car lightly used and I don’t know if it has a cabin air filter. Is there any way I can find that?


The owner’s manual should tell you if it does. If the owner’s manual says nothing about a cabin air filter, you don;t have one.

RTM (read the manual) also you should check or blow out the ac water drain .

Previous owner’s dog or child may have barfed on the dashboard and it got into the air vents.

But more likely, as barkydog suggests, your AC condensate drain tube may be blocked, in which case water is collecting inside the dash and allowing mold to grow and cause the smell. The drain tube can be unblocked by having a mechanic blow compressed air into it.

After you have the vent tube cleared, you can try to kill the mold by turning on the AC, setting the selector knob to “outside air” ( not “recirculate” ), turning the fan to high, then spraying a whole can of Lysol through the air intake grill at the base of the windshield.

PS…if the smell is only when the AC is on, then it’s probably not barf, which you would smell when the heat was on too. Most likely mold.

You do want to get this fixed quickly. Breathing in mold is risky for your health.

What about the warranty? Is it still covered? Check with Mazda. Also, if you don’t have the owners manual you can download it at

What 2011 cars don’t have pollen filters?

Get an A/C aerosol deodorizer that you use on recirculate & MAX with the doors shut, engine running and put the aerosol on the middle of the rear floor on what would be the transmission tunnel.

Did this with my Mazda 6 once I changed the pollen filter and all was well. Vent car well afterwards…